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Biomedical subjects

B Jansson

Publications and source records attributed to B Jansson.

At least 91 records · Page 5Linked to original sources
PubMed1990

Three-dimensional anatomy of the human endolymphatic sac.

Computerized and graphic three-dimensional reconstruction of a human endolymphatic duct and sac (ES) showed the ES to be a fusiform and flattened structure with marked tubularity, especially in the extraosseous region. The specimen was 18.2 mm long. It measured 60 X 200 microns at the isthmus portion of the endolymphatic duct and 200 X 7000 microns at the broadest part of the ES. The volume of the endolymphatic duct was 0.03 mm3 and of the ES, 1.85 mm3. The extraosseous ES volume represented more than two thirds of the total ES volume.

Computer Graphics↗
PubMed1990

The concept of cancer--a theoretical note.

System-oriented models are valuable in several scientific fields, but have been most utilised in accident research in order to prevent material damage and personal injuries from uncontrolled energy. Cancer research is very active and large efforts are made to understand how the cell growth control is disturbed. However, a computerised search on cancer theory revealed only a few articles on the subject. Therefore it is of interest to present a system-oriented approach to the cancer process. This approach could thereby serve as one step towards a more general theory of the cancer problem.

Environment↗
PubMed1990

A dual-affinity gene fusion system to express small recombinant proteins in a soluble form: expression and characterization of protein A deletion mutants.

A novel gene fusion system to express and purify small recombinant proteins in Escherichia coli has been constructed. The concept allows for affinity purification of soluble gene products by sequential albumin- and Zn2(+)-affinity chromatography. The dual-affinity system is well suited for expression of unstable proteins as only full-length protein is obtained after purification and proteins gain proteolytic stability in the fusion protein. Here we show that the dual-affinity approach can be used for the expression of various unstable derivatives of a single IgG-binding domain based on staphylococcal protein A. Analysis of the proteolytic stabilities and the IgG-binding properties of the different mutant proteins suggest that the model for the structure of an IgG-binding domain must be re-evaluated.

Base Sequence↗
PubMed1990

Accident involvement and attitudes towards hazards and countermeasures in a Swedish rural population.

Research on the resistance to implementation of effective injury control measures is needed. An important task is to identity factors or circumstances that influence the possibilities of taking active safety measures, and also factors that may limit or hinder such efforts. The objective of this study was to describe the farmers' own attitudes towards farm accident hazards and their interest in participating in preventive measures. The study is part of a project to develop systems for injury surveillance and control in Swedish emergency care. A standardised questionnaire for telephone interviews was used. All patients who had consulted an emergency department during a one-year period for injuries caused by accidents on 2,454 farms in two Swedish rural municipalities were interviewed. The results demonstrated that adults, especially young adults with small children, seem to be most conscious of accident risks and best motivated for participation in active safety measures, e.g. safety education.

Accidents, Occupational↗
PubMed1990

The stability of flumazenil in infusion solution.

Flumazenil, the first benzodiazepine antagonist to be marketed, is available only for intravenous injection (0.1 mg/ml). The half-life of the compound in plasma is short compared with that of the conventional benzodiazepines, and administration of the drug as a continuous infusion is therefore frequently required. However, the stability of flumazenil in infusion solution has not previously been known, which has meant that controlled studies of the drug in this administration form have been difficult to perform. In the present study, infusion solutions of flumazenil in concentrations of 1.0 and 5.0 micrograms/ml were produced and stored for periods of up to 9 months. The concentrations of the drug in the different solutions were determined by gas chromatography at defined intervals, and were found not to change during the study period. We conclude that the stability of flumazenil in infusion solution is satisfactory.

Drug Stability↗
PubMed1990

Dietary, total body, and intracellular potassium-to-sodium ratios and their influence on cancer.

One of the greatest changes in the human diet, a change that has occurred only within the past few thousand years, is the immense increase in the intake of sodium (Na) caused by use of table salt in the preparation and preservation of food. At the same time, man's intake of potassium (K) has decreased. The result is that from Paleolithic times to modern times the dietary K/Na ratio has been reduced by a factor of about 20. Based on a comparison of modern people in civilized areas with the primitive Yanomamo Indians in South America (who do not eat salt but who do grow and eat potassium-rich cooking bananas), this factor may even be on the order of 100 to 200. Humans, who initially had to adapt to retain sodium from a sodium-poor diet and to excrete potassium from a potassium-rich diet, have not yet evolutionarily adapted to today's high-sodium, low-potassium diet. This failure has caused increased rates of a number of diseases in civilized man, among them cancer. The influence of the K/Na ratio on cancer development--first discovered by epidemiologic studies--has been confirmed by various means, such as dietary studies, gerontological studies, studies of relationships between hyper- and hypokalemic diseases and cancer, and review of the cellular changes of this ratio induced by carcinogenic and anticarcinogenic agents. Recently, animal experiments have also confirmed the results. The recommended dietary K/Na ratio should be well above 1, preferably 5 or higher, and the cellular K/Na ratio should be above 10.

Animals↗
PubMed1989

Thiol-directed immobilization of recombinant IgG-binding receptors.

A genetic engineering approach is described for directed immobilization of IgG-binding receptors to a thiol-containing matrix using a single cysteine residue. The cysteine residue is introduced into the C-terminal part of receptors based on staphylococcal protein A. Receptors containing one, two or five IgG-binding domains were produced in Escherichia coli and subsequently immobilized on thiopropyl-Sepharose. A high amount, 5 mumol/ml gel (45 mg/ml), of recombinant receptor could be rapidly immobilized to the solid support and both the gel and the immobilized receptor could be regenerated by reduction and oxidation reactions. The gel was used for affinity purification of human IgG and analysis of IgG-binding capacity at different amounts of immobilized recombinant protein show the same maximal IgG-binding capacity (20-25 mg/ml) for all three immobilized receptors. However, at low substitution grade of receptors, the immobilized receptor molecules were shown to bind one (Z-Cys) and two (ZZ-Cys) IgG molecules, respectively. These results demonstrate that the immobilized protein molecules are in a functionally active form and that a two-domain receptor can bind two molecules of IgG without steric hindrance. Interestingly, the five-domain receptor (ZV-Cys), with a structure similar to native protein A, can only bind approximately two IgG molecules, despite the five-domain structure of the molecule.

Amino Acid Sequence↗
PubMed1989

Rat serum antibodies binding to high-molecular-weight glycoprotein(s) on syngeneic colon carcinomas, demonstrated by competition with rat monoclonal antibody.

Sera from rats immunized to syngeneic 1,2-dimethylhydrazine colon carcinomas were analyzed for their ability to inhibit the binding of a syngeneic rat IgM monoclonal antibody (10B12) specific for high-molecular-weight glycoprotein(s) from rat colon carcinoma. Immunization with irradiated tumour cells or with tumour tissue extracts resulted in the appearance of a strong inhibiting activity. Sera of animals with established growing tumours and of females shortly after partus also inhibited binding of the monoclonal antibody, while unimmunized animals or animals immunized with irrelevant antigens had no inhibiting antibodies in their sera. Dimethylhydrazine-treated animals showed an increased titer of antibodies binding to the high-molecular-weight glycoprotein, but showed no inhibition of binding of the 10B12 monoclonal antibody. The syngeneic 10B12 rat antibody obviously does not reflect a rare event captured from a hyperimmune animal by the hybridoma technique but rather represents an antibody specificity frequently appearing in the immune response to tumours expressing the high-molecular-weight glycoprotein.

Animals↗
PubMed1989

Recognition of a high molecular weight glycoprotein (HMW-GP) associated with rat colon cancer cells by rat monoclonal antibodies.

In this report we describe an auto-immunogenic tumor associated high molecular weight glycoprotein (HMW-GP) present on most rat colon carcinomas as detected by syngeneic monoclonal IgM antibodies. The HMW-GP has an apparent molecular weight of more than 10(6) D and carries several epitopes for various lectins, carbohydrate specific mouse monoclonal antibodies and four rat syngeneic monoclonal antibodies. The epitope defined by the 10B 12 rat monoclonal antibody is present in colon carcinoma tissue, but only in very low amounts in normal gastro-intestinal-tissue. The epitope is present at multiple sites on the large molecule and is shown to be sterically related, but not identical to determinants for Dolichos biflorus lectin and a mouse mAB binding to blood group A. The 10B 12 mAB binding is insensitive to boiling, reduction with mercaptoethanol and treatment with trypsin, but abolished by pretreatment of the antigen with sodium periodate or neuraminidase. The epitopes defined by 1 G6 and 1F6 rat monoclonal antibodies are present both in tumor tissue and in normal colon mucosa and the antibody binding is increased after treatment with both neuraminidase and sodium periodate.

1,2-Dimethylhydrazine↗
PubMed1989

Evaluation of a system for injury surveillance in Swedish emergency care.

A system for continuous and periodic injury surveillance in Swedish emergency care has been evaluated based on a case study of accidental injuries on 2,454 farms during a one year period. The evaluation procedure comprised registry completeness, measurement errors, trend analysis and calculation of risk. The results indicate that the structure of the registry system permits analysis of registry completeness, but further development is needed concerning the staffing and organising problem. The importance of registry inclusion criteria when one is comparing different injury surveillance systems was noted. Limitations applied to calculation of accident frequency rates per million hours work. The results show that there will be a high drop-out rate if the collection of data is not simultaneously combined with an injury control programme. The registry system could serve as a basis for periodic surveys and trend analysis. Further development of a continuous system based on reporting immediately at the injury reception centre should be considered. A coordinated system involving both continuous and periodic data seems to leave the flexibility both to identify certain risk environments or risk groups and to analyse the circumstances involved of specific accidental injuries, e.g. in agriculture.

Accidents, Occupational↗
PubMed1989

Use of a monoclonal rat anti-mouse Ig light chain (RAMOL-1) antibody reduces background binding in immunohistochemical and fluorescent antibody analysis.

Rat monoclonal antibodies (MAb) directed to mouse Ig heavy and light chain determinants were produced. A rat anti-mouse light chain MAb (RAMOL-1) which bound to all (24/24) mouse Ig of the kappa light chain type and with varying strength to 4/4 lambda light chain-bearing Ig was evaluated as a general secondary reagent, together with two MAb that bound to the heavy chain of mouse IgG. They were conjugated with biotin or FITC and used in immunohistochemical and immunofluorescence assays to detect mouse monoclonal antibodies binding to antigens expressed in rat and human tissues and cells. As compared to commercially available polyclonal reagents, RAMOL-1 gave higher staining contrast by showing lower background staining and equal or higher staining of the primary MAb tested. This was a result of two main effects. First, crossreactivity with endogenous Ig and tissue type-specific determinants was eliminated. With polyclonal anti-mouse Ig reagents, binding to endogenous Ig was noted in vascular spaces and on Ig-bearing cells, and to rat gastric mucosa and epithelial tumor tissue in frozen tissue sections, even when diluted in high concentrations of serum homologous to the tissue. Second, binding of the secondary reagent was reduced to cells and tissues prone to have high nonspecific binding capability, such as monocytes/macrophages and formalin-fixed, paraffin-embedded tissue. Owing to unlimited and reproducible access to this homogeneous reagent, RAMOL-1 is used as second antibody to standardize the procedure used for immunohistochemical grading of human malignant tumors by determination of blood group antigen expression detected with mouse MAb.

Animals↗
PubMed1989

Effects of hyperosmolar substances on the endolymphatic sac.

The murine endolymphatic sac (ES) was studied 15 min to 8 hours after intravenous glycerol administration. Initially the ES showed varying degrees of obliteration and this was mostly pronounced at 15-60 min after the injection. After 2 hours the normal volume was regained and after 4 hours the lumen was dilated to 160% of its normal volume. After 6-8 hours the ES had almost regained its normal appearance. The epithelial lining showed an increase in the number of granular cells which, after two hours, reached a peak of 15.8% (p less than 0.01) compared to normal controls which showed 6.1% granular cells of total cell population in the ES. The increase of granular cells was accompanied by filling of the ES lumen with a stainable substance. The epithelial reaction may serve the purpose of counteracting decreases in endolymph pressure either in the ES or in the entire labyrinth.

Animals↗
PubMed1988

A biotin-labelled antigen radioimmunoassay (BILA) for antibodies to membrane antigens useful for monoclonal antibody screening.

Viable cells or protein extracts were labelled with N-hydroxysuccinimidobiotin and used as target antigens in a biotin-labelled antigen radioimmunoassay (BILA). The binding of the biotinylated antigens to capture antibodies coated on the bottoms of 96-well plastic plates were measured using 125I-labelled streptavidin as the detection step. The assay circumvents some of the problems associated with solid-phase RIA and permits screening of antibodies to undefined protein antigens present in very small amounts in complex protein solutions.

Animals↗
PubMed1988

Subcellular changes in the endolymphatic sac after administration of hyperosmolar substances.

The effects of hyperosmolar substances on the ultrastructure of the endolymphatic sac were studied in mice. Fifteen minutes after intravenous injection of urea or glycerol, subcellular changes in the endolymphatic sac were observed. These consisted of the occurrence of abundant cytoplasmic granules with a floccular or lamellar material, or both, in the light epithelial cells. Similar material was also present in the lumen of the endolymphatic sac, suggesting a common source and increased secretory activity. Mannitol caused similar changes, though less pronounced. The possibility that the alterations in the fine structure of the endolymphatic sac may be associated with a reduction in the hydrostatic fluid pressure in the rest of the labyrinth is discussed.

Animals↗
PubMed1988

Variations in surgical anatomy of the endolymphatic sac.

Twenty-nine specimens of the extraosseous portion of the human endolymphatic sac (ES) were serially sectioned longitudinally. The length and width of the extraosseous ES were measured and the surface area was calculated. As the specimens included the sigmoid sinus (SS), the relationship between the ES and the SS was analyzed. The extraosseous ES varied considerably in size. The lumen either consisted of a single tube or was subdivided into several tubules. The distal part of the ES overlapped the SS in one third of the specimens. The results indicate that a minute extraosseous ES could explain the sometimes difficult task of localizing this structure at ES surgery. The great variability in size might perhaps also explain the varying results of this surgery.

Adult↗
PubMed1988

Experiences from a psychiatric service to immigrant groups using native therapists.

Experiences from an out-patient department giving psychiatric service in their own language to three immigrant groups to Sweden, namely Finnish, Yugoslavian and Greek patients are described. Compared to Swedish patients, depressive disorders and alcohol abuse were much less common among the patients from southern Europe, who instead showed much more of psychosomatic distress. Treatment results were not too encouraging, a negative social situation of the patient was often difficult to change. In the future, the author considers it advantageous to have one psychiatric immigrant department for one nationality at one place and to connect it to an already existing department for Swedish patients.

Acculturation↗
PubMed1988

Indoor radon exposure and active and passive smoking in relation to the occurrence of lung cancer.

Exposure to indoor radon and radon daughters is currently attracting great interest as a possible cause of lung cancer. This concern is supported by several studies, most of them relatively small in numbers or weak in the assessment of exposure. This study encompasses 177 persons with lung cancer and 677 noncancer referents, all deceased and with 30 years or more of residency in the same house in an area with radon-leaking alum shale deposits in the central part of southern Sweden. Exposure categories based on building material, type of house, and ground conditions were created, but measurements of the indoor radon daughter concentration were also made for 142 cases and 264 referents. Active and passive smoking was ascertained through questionnaires sent to the next-of-kin. Overall, the lung cancer risk was approximately twofold with regard to the categories of assumed radon daughter exposure for the rural sector of the population but not for the same categories of the urban sector, possibly because of less precise exposure assessment and influence from other factors. Occasional and passive smokers, as well as passive smokers alone, had a particularly increased risk of lung cancer in association with the increased exposure categories.

Adult↗